A power tool or the like proposed in the prior art is driven by an electric motor supplied with power from a rechargeable battery and includes, in regard to protection of the rechargeable battery, a means for detecting the voltage of a battery cell of the rechargeable battery and a means for determining an abnormality (over-discharge) when the voltage value becomes less than a determination value and controlling the supply of power to the motor, that is, stopping the operation of the power tool (for example, refer to patent document 1).
Patent Document 1: Japanese Laid-Open Patent Publication No. 10-27630